Ladder jack



Jan. 8, 1946. v

w. H. WALKER 2,392,347 I LADDER JACK Filed A ril 20, 1945 l I l INVENTOR.

Patente an,- 9 6 UNITED STATES PATENT ()FFICE] LADDER JACK I William Henry Walker, Sarasota, Fla. Application April 20, 1945, Serial No. 589,355

3 Claims.

This invention relates to ladder jacks which are commonly attached to two ladders placed in parallel positions against the wall of a building at a convenient distance apart, to support a plank upon both said jacks and ladders as an improvised scaffold for painters, carpenters, 'glazlers or other workmen to stand thereon.

The primary object of my invention is to provide a ladder jack of simple, practical and strong construction, free of all complicated parts and modes of adjustment and operation, which may speedily be affixed to each ladder with one brief movement of attachment, and as readily removed therefrom, with no loss of time or need to study directions; which will hold fast and tightly with.

no danger of slipping, will support the crossplank solidly and safely; which can be fitted upon ladders of slightly varying widths firmly. and

snugly and will be automatic in its adaptation to such different ladders; which will have means for making simple adjustments of each jack so that in the case of unlevel ground suflicient to disturb the level of the plank upon the ladders, one or both may be slightly adjusted to compensate;

which will grip the ladder in a double engagement ings in various conditions and uses, as for example, upon steel windows in glazing the same, the

jacks being connected to the steel windows by" insertion of the grips thereof into the unglazed pane-stiles.

With these and other subordinate objects in view, my invention consists in the novel elements,

features, factors or operative parts, and in the novel construction and arrangement thereof, set forth in this specification.

In the accompanying drawing forming part of this specification, in which like numerals of reference designate like parts in the several views:

Figure 1 is a side elevation of my newly invented ladder jack applied upon a ladder;

Figure 2 is a front elevation of the same;

Figure 3 is a top plan view thereof.

In the practice of my invention I construct vertical bars I, I, which range longitudinally of the ladder when in situ, and diagonally inwardly from the uprights of the ladder to the medial line of the rung or rungs beneath. Near their tends. r I 7 provided with two bolt-roles I9, 20; one of which lower ends, they are obtusely bent from their descending mutual approach shown in Figure 1, into an angled parallelism in the form of flanges or extensions 2, 2, which project practically straight down with just a slight outward flare so that any space left between them in completely assembled form, will be appreciably wider at the bottom, for a purpose which will hereinafter appear. I

At the top of each vertical bar I I attach firmly, or form thereon or therewith, a U-shaped yoke or gripping member 3, which may be welded, riv eted, or otherwise mounted thereon, or maybe formed integrally therewith. These two yokes 3, have their mouths facing front to embrace the ladder-uprights from behind and upon the sides. The outer arm 4 of each yoke is shorter than'the inner bar 5, the end of which projects in the shape of a bent or curved extension 6 which is Welded upon the top of the vertical bar I, or may be formed integrally therewith. This curvedextension 6 rests upon the rung of the ladder while the elbow or rear bar I of the yoke 3 is in contact with the back of the upright.

Near the top' of each vertical bar I is punched a bolt-hole 8, through which is inserted, to move somewhat freely, a bolt 9, provided with a nut I0. Upon these bolts are mounted the plank-supporting bars II, which range substantially horizontally and diagonally inwardly to meet in front of the ladder in line with the extensions or flanges 2 of the vertical bars], and thus in front of the medial line of the rungs of the ladder. The inner or rear ends of tire bars ll'are formedinto extensions or flanges I2, orific'ed to receivethe bolts 9' therethrough; the said flanges being angled to lie flat against the inner faces of the bars I, where they are secured'by the nuts I0, not tightly screwed up, but with some measure of play left. The bars II are thus positioned with their edges up, and are formed with flanges or extensions I3 at their front ends, bent to he fairly flat together, and orificed to receive a quite long bolt I 4, provided with nut I5.

From these front'flanges 13 of the bars II depends a brace bar I6, uniformly straight throughout. Its upper end is provided with two boltholes I'I,' I3, through one of which the bolt I4 ex- The lower end ofthe brace bar IB is also receives abolt 2!, which passes through the flanges or extensions 2, 2, at th'e'lowerend-of the vertical bars I, and is provided with a nut 22. The brace bar It fits between the two fia'nges 2, 2 and the bolt I6 is long enough to allow a material amount of play, the nut 22 not being tightly screwed up. I As shown, all the bars are made of flat metal strips of stamped, pressed or wrought iron, or of;

diagonal, because each is mainly and primarily so" directed, all the bars are in fact diagonally disposed in addition; the vertical andhorizontal bars being inclined toward each other almost to meeting. The jack is therefore triangular in appear ance seen from various angles of top, bottom, back, front, sides; this being a descriptive and definitive statement, not limiting, not indicative of any special function thereby, except that it may.

be .seen that the-balance of the parts, of the strains upon the jack, is evenly and accurately, calculated and taken care of.

, In the operation of my newly invented ladden jack, as applied to ladders for constructing an immediate scaffold or equivalent of one, having first assembled it as shown in the drawing, I take the yokes or gripping members 3 in both hands, or the horizontal bars H in both hands, and bring them'together nearer, so as partly to close cr fold the jack say half-way, thus fitting it to be the most easily inserted in the middle of the lad- ,der, between the uprights, and above one of the rungs, at whatever-height upon the ladder it is desired to have the plank supported. The shape of the jack after this scissors folding action is indicated in dotted lines in Figure 3. Then the yokes are pushed rearwardly into the ladderopening, the jack being slightly tipped up in doing so, and the frame of the jack is given a reverse'scissors motion of unfolding or widening out; to bring the elbow 1 of each yoke directly back of the adjacent ladder-upright, ready to encircle or clasp the same from the rear, with the curved extension 6 of the yoke resting upon the rungof'theladder; whereupon the jack is pulled forwardly to clamp the yokes around the uprights its structure, enable it to be employed with equal facility and efiectiveness upon ladders of slightly varying widths, and in fact, I believe, covering the whole range of variation of such ladders as are used by workmen upon buildings.

Those who have hitherto used jacks upon ladders for the indicated purpose, will be aware that when the jacks are attached upon a pair of such ladders, as above described, the said ladders are setagainst the building at such distance apart as desired, to cover and work upon whatever area thereof as accord with the length of the plank to 'be used, or a lesser space if no more is to be cov- 'the weakening of the immobility of the support.

The clamping of the yokes, the pressure of the elbow thereof againstthe'back of the uprights, press the curved bends 5 down upon the rung whereon they rest, and likewise prevent by their clasp of the upright, all. the weight being borne by said rung, which admittedly is the weakest part of a ladder. There is a double clamping action, in which the most weight is carried by the uprights, while immobility and security are attained bythe joint support of both upright and rungseating. And the pressure of the flanged ends of the vertical bars and the diagonal brace bar with the bolts to the upper and lower ends of said brace with the elbows 'l'closely engaging the back of the said'uprights, and the curved or bent extensions #6 bearing down upon the ladder-rung beneath them, while'the lower ends of the vertical bars I andof'the brace bar therein, are seated in front of and against one of the lower rungs of the ladder. :the ladder as shown in full lines in the several The jack will then be positioned upon figures of the drawing.

It will be noted that the long and loose bolt I4, which holds together the horizontal plank-supporting bars H with the top ofthe brace bar 16 between their front flanges l3; and the lower bolt 21 which unitesthe lower flanged ends 2 of the vertical bars I, with thelower ends of the brace, bar I 6 between them, both allow such play of the connected parts as to permitthis scissors motion of the jack, in its partiolded and unfolded vari- V ations, and render unnecessary the introduction of separate hinging expedients on either side of the brace bar, top or bottom, although I may employ such alternatives in additionor in place bar, with concomitant effect of adjusting the thrust of the brace bar and vertical bars against the lower rung of the ladder, and adjusting the angle of level of the horizontal planksupporting bars. When the jack is once set in its'best position upon the ladder, it rarely needs any adjustment on that particularladder. The chief occasion for adjustments in usedaily, arises from the employment of the jacks necessarily in pairs upon spaced ladders, thus sometimes necessitating-relative adjustments of the two jacks intense, and almost invariably when unlevel ground places one ladder-base upon a difierent plane from the other, and thus calls for some compensatory re-arrange ment of the two jacks to secure the proper level of the plank throughout its length.

The manner of employment oft-he jacks upon a building directly, as in the case of a steel-wine dowed structure it is desired to glaze after erection, is readily understandable from the foregoing description of its application upon the pair of ladders, it being noted that the yokes 3 are caught around the pane-stilesof two unglazed windows. at a desired distance apart for placing the planksupporting jacks thereon. The glazing or other work of course starts from-the top, the plank being set immediately below the work, and constantly lowered as the work progresses, until ground is reached, from which the final section of the work is completed.

The jack may be as easily removed from the ladder or other supporting body, by the exact reverse of the affixing operation above described, the facility of partially folding the jack being the same as in applying it. The flaring outwardly of the flanges 2, 2 of the vertical bars I, I, enables these flanges to open up further than if they were quite straight, so that the jack may open enough to be fitted to the uprights of the ladder, or other supporting body.

While the specially simplified structure of my invention has reduced it to factors and features each, and all collectively, functional in the operation as above described, I am conscious that minor variations may be made therein from time to time, without departing from the substance of my said invention, as herein set forth and as hereinafter defined; for no other jack, with these few parts of easy making and operating, ever embodied the unusual features of three point support of all the weights and strains of jack, plank and workmen thereon, first on the rung at top, then simultaneously against the rear of the ladder uprights on forward pull, and lastly bytransmission through the diagonal brace to the lower end of the vertical bars in added pressure against the lower rung of the ladder, while the sides of the yokes tend to engage the sides of the uprights adding holding power there, as well as withstanding any tendency to lateral slipping of the jack.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is: I

1. A ladder jack composed of vertical bars which lie against the front of the ladder and range diagonally inwardly to substantially meet at the median line of a, lower ladder rung beneath the one at which the jack is set, horizontal plank-supporting bars attached thereto at top and projecting diagonally forwardly to substantially meet at the front of the median line of the rung at which the jack is set, a diagonal brace bar connected at its upper end to the horizontal bars and resting between the same, and leading diagonally downward to the lower ends of the vertical bars and resting between the same, means for connecting the several bars together at each end of the brace bar, and passing through said brace bar, in such pivotal relation as to permit lateral folding of the jack part way to enable it to be inserted in a ladder opening, and widened out again for engagement with the uprights thereof, and yokes at top of the jacks, at each side thereof, resting upon a rung of the ladder at a point where the jack is set, and also engaging around the uprights of the ladder to bear against the rear of said uprights at the same time that they engage and rest upon the ladder rung.

2. A ladder jack composed of vertical bars which lie against the front of the ladder and range diagonally inwardly to substantially meet at the median line of the ladder, and being provided with flanges at the bottom of said bars,

horizontal plank-supporting bars mounted at top of said vertical bars and projecting diagonally forwardly to substantially meet at front at the median line of the ladder, and having flanges at both rear and front ends thereof, a diagonally and. rearwardly ranging brace bar lying between said horizontal bars and said vertical bars, bolts extending freely through the flanges of the vertical bars and the horizontal bars at both top and bottom of said brace bar, and holding them in such loose relation as to permit partial folding thereof together to narrow the jack for insertion and widen it for engagement, and yokes mounted upon the vertical bars at the top of the jack at each side, and resting upon a ladder rung next under the jack, and projecting around the ladder uprights with their outer members engaging the outside of the uprights and their elbows engaging the rear of said uprights.

3. A ladder jack composed of vertical bars adapted to lie against the front of the ladder and which are directed downwardly and inwardly with their lower ends adapted to bear against a lower ladder rung beneath the one on which the jack is set, yokes mounted upon the top of the said vertical bars at each side of the jack formed to enter between the uprights of the ladder and to clasp around the said uprights from inside thereof to outside, and to rest upon and above a rung of the ladder as well, with the inner members of the yokes engaging the inner faces of the uprights, and the outer members thereof engaging the outer faces of said uprights; horizontal plank-supporting bars mounted upon said vertical bars near the top thereof, and projecting forwardly and inwardly, a downwardly and rearwardly projecting brace bar mounted centrally in the forward ends of the plank-supporting bars, and mounted at its lower end in the lower ends of the vertical bars, whereby the said jack may be quickly inserted in the ladder, and the vertical bars carry the strain of the jack and the workmen 0n the plank, upon and around the uprights and the contiguous rung, and upon a lower rung against which the vertical bars impinge, and whereby the brace bar ranging from the outer end of the horizontal bars to the lower ends of the vertical bars may carry all further strains of said weight additionally in the direction of both vertical pull upon the said vertical bars in clamping the yokes about the uprights and upon the contiguous ladder-rung, and against the lower rung so impinged by said vertical bars.

WILLIAM HENRY WALKER. 

